The present invention relates to mounting structure for optical instruments and, more particularly, to such an instrument which enables the position of an optical device with respect to an optical axis to be accurately adjusted. The invention more specifically relates to a laser which includes a simple mounting structure providing precise and stable angular reorientation of the laser end mirrors with respect to the optical axis of the lasing tube.
It is important in most optical instrumentation that optical devices of one sort or another, such as lenses, mirrors, prisms, etc., be precisely positionable with respect to an optical axis. For example, proper operation of a laser depends on precise and stable angular alignment of the optical reflectors (mirrors) at the opposite ends of the lasing medium envelope. Such alignment is necessary to assure that the requisite number of passes of the optical radiation through the lasing medium are effected for laser oscillation. Moreover, it is desirable that such alignment be precisely and reproducibly adjustable to enable differing wavelength outputs and optimization of the output power.
Much effort and time has been spent by those in the art in attempts to arrive at a satisfactory mirror mounting structure for lasers providing the desired stable positioning while allowing precise angular reorientation. It is now generally accepted that such a mounting mechanism preferably provides independent rotational movement of the mirror about at least two perpendicular axes to assure that any desired angular setting can be achieved. However, the apparatuses which have been designed in the past to provide such adjustments have not been entirely satisfactory. They are, in general, relatively complicated and do not provide the precise and stable positioning desired. For example, some of such devices have included coil springs extending between the mirror mount and a reference structure. Such springs generally interfere with the stableness of any given mirror setting and the sensitivity with which changes can be made. Prior mounting structures often have also included tieing structure of one sort or another between the mirror mount and the reference structure to maintain mirror settings rigid, which tieing structure has interfered with truly independent movement about the perpendicular axes.